title: RpoS and oxidative stress conditions regulate succinyl-CoA: 3-ketoacid-coenzyme A transferase (SCOT) expression in Burkholderia pseudomallei.
abstract: Burkholderia pseudomallei, a pathogenic gram-negative bacterium, causes the severe human disease melioidosis. This organism can survive in eukaryotic host cells by escaping reactive oxygen species via the regulation of stress responsive sigma factors, including RpoS. In B. pseudomallei, RpoS has been reported to play a role in the oxidative stress response through enhanced activity of OxyR and catalase. In this study, the RpoS dependent oxidative stress responsive system was further characterized using comparative proteomic analysis. The proteomic profiles of wild-type B. pseudomallei following exposure to H2 O2 and between wild-type and the rpoS mutant strains were analyzed. Using stringent criteria, 13 oxidative responsive proteins, eight of which are regulated by RpoS, were identified with high confidence. It was observed that ScoA, a subunit of the SCOT enzyme not previously shown to be involved directly in the oxidative stress response, is significantly down-regulated after hydrogen peroxide treatment. ScoA and ScoB have been predicted to be organized in a single operon using computational methods: in this study it was confirmed by RT-PCR that these genes are indeed co-transcribed as a single mRNA. The present study is the first to report a role for RpoS in the down-regulation of SCOT expression in response to oxidative stress in B. pseudomallei.
authors.affiliation: Department of Biochemistry, Mahidol University, Nakhon Pathom, 73170, Thailand.
authors.forename: Palatip
authors.initials: P
authors.lastname: Chutoam
authors.forename: Varodom
authors.initials: V
authors.lastname: Charoensawan
authors.forename: Patompon
authors.initials: P
authors.lastname: Wongtrakoongate
authors.forename: Apiratana
authors.initials: A
authors.lastname: Kum-Arth
authors.forename: Pisanu
authors.initials: P
authors.lastname: Buphamalai
authors.forename: Sumalee
authors.initials: S
authors.lastname: Tungpradabkul
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D016957:Burkholderia pseudomallei / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D015256:Coenzyme A-Transferases / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008554:Melioidosis / Q000382:microbiology; D018384:Oxidative Stress / Q000187:drug effects; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria; D006861:Hydrogen Peroxide; D015256:Coenzyme A-Transferases; C021460:3-ketoacid CoA-transferase
keywords: Burkholderia pseudomallei; RpoS; oxidative stress; succinyl-coA:3-ketoacid-coenzyme A transferase